Xeromammography is an important radiological technology because of it ability to highlight microcalcifications, a primary indication of the presence of cancer. This ability is due to the inherent edge-enhancement of xerography. Until the advent of film-phosphor screen systems, xeromammography provided images with the lowest patient dose. Presently, xeromammographic systems are about half as sensitive as film-screen systems. This sensitivity is limited by the photoconductor detector plate which are made of amorphous selenium-a-Se). Our Phase I research has demonstrated that high sensitivity photoconductive plates can be produced from a "new" semiconductor material, thallium bromide (TlBr). Due to its high X-ray stopping power and good charge carrier transport properties, we calculate that TlBr xerographic photoconductor plates will be almost 4 times as sensitive as the a-Se plates presently being used. Additionally, we have producted TlBr films of the appropriate thicknesses with relative ease. During Phase II, research will be performed with the goal of fabricating and testing TlBr photoconductor plates and producing actual xerograms. To accomplish this, we will need to adapt our TlBr deposition process to accommodate larger area films, identify suitable substrates, and investigate methods to incorporate cooling the photoconductor. Finally, we will measure the TlBr photoconductors' sensitivity under actual xerographic conditions.